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<a href="http://sim.okawa-denshi.jp/en/CRtool.php" class="menu">Sample calculation</a>
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RC Low-pass Filter Design Tool
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This page is a web application that design a RC low-pass filter.
Use this utility to calculate the Transfer Function for filters at a given frequency or values of R and C.
The response of the filter is displayed on graphs, showing Bode diagram, Nyquist diagram, Impulse response and Step response.<br>
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<b><font color="#000080">♦</font>Filters</b><br>
<a href="http://sim.okawa-denshi.jp/en/CRlowkeisan.htm">RC LPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/CRhikeisan.htm">RC HPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/LRlowkeisan.htm">LR LPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/LRhikeisan.htm">LR HPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/RLClowkeisan.htm">RLC LPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/RLChikeisan.htm">RLC HPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/RLCbpkeisan.htm">RLC BPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/RLCbekeisan.htm">RLC BEF</a><br>
<a href="http://sim.okawa-denshi.jp/en/OPseikiLowkeisan.htm">Sallen-Key LPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/OPseikiHikeisan.htm">Sallen-Key HPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/Sallenkey3Lowkeisan.htm">3rd order SallenKeyLPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/Sallenkey3Hikeisan.htm">3rd order SallenKeyHPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/OPtazyuLowkeisan.htm">Multiple feedback LPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/OPtazyuHikeisan.htm">Multiple feedback HPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/OPtazyuBakeisan.htm">Multiple feedback BPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/MultipleFB3Lowkeisan.htm">3rd order Multiple feedback LPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/MultipleFB3Hikeisan.htm">3rd order Multiple feedback HPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/TwinTCRkeisan.htm">TwinT notch</a><br>
<a href="http://sim.okawa-denshi.jp/en/CRCRkeisan.htm">CR 2nd order LPF,HPF,BPF</a><br>
<a href="http://sim.okawa-denshi.jp/en/opampkeisan.htm">Active filter</a><br>
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<font size="-1"><a href="http://sim.okawa-denshi.jp/en/Fkeisan.htm">Filter index</a></font>
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<h5>Calculate the transfer function for low-pass filter with R and C values</h5>
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<td>Vin(s)→</td>
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<img src="a500%20%231%20filter%201a_pliki/CRLowPass.png" border="0">
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<td>→Vout(s)</td>
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<img src="a500%20%231%20filter%201a_pliki/CRLowD.gif">
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<form action="CRtool.php" method="post">
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<td width="50%">R=<input value="360" name="p1" maxlength="15" size="9" type="text">Ω</td>
<td width="50%">C=<input value="0.1u" name="p2" maxlength="15" size="9" type="text">F</td>
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p:pico, n:nano, u:micro, k:kilo, M:mega
<br>
<fieldset>
<legend><span>Frequency analysis</span></legend>
<input name="fa1" checked="checked" type="checkbox">Bode diagram<br>
<input checked="checked" name="fa2" type="checkbox">Nyquist diagram(f=0→∞)<br>
<input name="fa3" checked="checked" type="checkbox">Pole, zero<br>
<input checked="checked" name="fa4" type="checkbox">Phase margin<br>
<input checked="checked" name="fa5" type="checkbox">Oscillation analysis<br>
</fieldset>
<fieldset>
<legend><span>Transient analysis</span></legend>
<input name="ta1" checked="checked" type="checkbox">Step response<input checked="checked" name="ta2" type="checkbox">Impulse response<br>
<input checked="checked" name="ta3" type="checkbox">Overshoot<br>
<input name="ta4" checked="checked" type="checkbox">Final value of the step response<br>
</fieldset>
<input name="com" value="1" type="hidden">
<p align="right"><input value="Calculate" type="submit"></p>
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</form>
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<h5>Calculate the R and C values for the filter at a given frequency</h5>
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<td>Vin(s)→</td>
<td>
<img src="a500%20%231%20filter%201a_pliki/CRLowPass.png" border="0">
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<td>→Vout(s)</td>
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<img src="a500%20%231%20filter%201a_pliki/CRLowfc.gif">
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<form action="CRtool.php" method="post">
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<tbody><tr><td width="100%">f<sub>c</sub>=<input name="p1" maxlength="15" size="9" type="text">Hz</td></tr>
<tr><td width="100%">C=<input name="p2" maxlength="15" size="9" type="text">F (Omitted C=10, 1, 0.1, 0.01…)</td></tr>
<tr><td width="100%">p:pico, n:nano, u:micro, k:kilo, M:mega</td></tr>
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Select Resistor Sequence:
<select name="keiretu">
<option value="24" selected="selected">E24</option>
<option value="12">E12</option>
<option value="6">E6</option>
<option value="96">E96</option>
</select>
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<font size="-1">
<br>
<fieldset>
<legend><span>Frequency analysis</span></legend>
<input name="fa1" checked="checked" type="checkbox">Bode diagram<br>
<input name="fa2" type="checkbox">Nyquist diagram(f=0→∞)<br>
<input name="fa3" checked="checked" type="checkbox">Pole, zero<br>
<input name="fa4" type="checkbox">Phase margin<br>
<input name="fa5" type="checkbox">Oscillation analysis<br>
</fieldset>
<fieldset>
<legend><span>Transient analysis</span></legend>
<input name="ta1" checked="checked" type="checkbox">Step response<input name="ta2" type="checkbox">Impulse response<br>
<input name="ta3" type="checkbox">Overshoot<br>
<input name="ta4" checked="checked" type="checkbox">Final value of the step response<br>
</fieldset>
<input name="com" value="2" type="hidden">
<p align="right"><input value="Calculate" type="submit"></p>
</font>
</form>
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<hr size="1">
<h5>RC Low-pass Filter Design for PWM</h5>
<p align="right"><a href="http://sim.okawa-denshi.jp/en/PWMtool.php" class="menu">Sample calculation</a></p>
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<td align="center"><img src="a500%20%231%20filter%201a_pliki/PWM_sign.png"><br>PWM signal</td>
<td>→</td>
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<img src="a500%20%231%20filter%201a_pliki/CRLowPass.png" border="0">
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<td>→Vout(s)</td>
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<p align="left">
<font size="-1">
A simple RC low-pass filter can convert a PWM signal to an analog signal as cheap D/A converter.
This tool calculate peak-to-peak ripple voltage and settling time.
</font>
</p>
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<form action="PWMtool.php" method="post">
<table class="ss" width="100%">
<tbody><tr><td width="100%">f<sub>PWM</sub>=<input name="fpwm" maxlength="15" size="9" value="10k" type="text">Hz</td></tr>
<tr><td width="100%">Duty Step&nbsp;&nbsp;&nbsp;&nbsp;0%→<input name="sd" maxlength="10" size="5" value="50" type="text">[%]</td></tr>
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PWM signal voltage<br>
&nbsp;V<sub>L</sub> = <input name="vl" maxlength="10" size="5" value="0" type="text">[V]&nbsp;&nbsp;V<sub>H</sub> = <input name="vh" maxlength="10" size="5" value="5" type="text">[V]
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<fieldset>
<legend><span>R and C values of filter | Cut-off frequency</span></legend>
<input name="tset" value="1" type="radio">Cut-off frequency&nbsp;&nbsp;fc = <input name="fc" maxlength="15" size="9" type="text">[Hz]<br>
<input name="tset" value="2" checked="checked" type="radio">R and C values<br>
<table class="ss" width="100%"><tbody><tr>
<td width="50%">&nbsp;&nbsp;&nbsp;&nbsp;R=<input name="p1" maxlength="15" size="9" type="text">Ω</td>
<td width="50%">C=<input name="p2" maxlength="15" size="9" type="text">F</td>
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</fieldset>
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<font size="-1">
p:pico, n:nano, u:micro, k:kilo, M:mega<br>
<br>
<input name="com" value="1" type="hidden">
<p align="right"><input value="Calculate" type="submit"></p>
</font>
</form>
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